1. Field of the Invention
The invention relates to a hydrocarbon conversion process. The invention specifically relates to the alkylation of hydrocarbons such as aromatics or paraffins to produce useful chemicals and motor fuel. The invention is primarily directed to a process for the solid bed alkylation of isobutane to produce C.sub.8 isoparaffins useful as motor fuel blending components.
2. Related Art
The utility of alkylation reactions and the passage of time has led to the development of a number of effective alkylation technologies which are employed in large scale commercial facilities. One of the most widely used processes for the production of motor fuel is HF alkylation as described in U.S. Pat. No. 4,139,573 issued to D. B. Carson. This reference provides an overview of the HF alkylation process and also describes the use of indirect heat exchange to vaporize butanes as a means of removing heat from the reaction zone.
U.S. Pat. No. 4,849,569 issued to L. A. Smith, Jr. describes a solid bed alkylation process employing catalytic distillation to react a C.sub.2-C.sub.10 olefin with an aromatic hydrocarbon. In catalytic distillation the heat of reaction is allowed to vaporize a portion of the liquid phase reactants present in the mixed-phase conditions of the contacting media present in the reaction zone thereby removing heat from the reaction zone. This patent describes the use of aluminosilicate molecular sieves as a catalyst. U.S. Pat. No. 4,950,834 issued to R. P. Arganbright et al. describes the production of cumene by the reaction of propylene and benzene using two different catalysts in a catalytic distillation zone. The two catalysts contain Y zeolite and omega zeolite respectively.
Yet another design for a solid catalyst alkylation process is described in U.S. Pat. No. 5,133,942 issued to E. M. Jones. This patent describes the use of removable catalyst retained upon distillation trays to perform the alkylation, with a drawoff being provided on each tray for the removal of slurried catalyst. The rising vapor is described as keeping the catalyst in suspension.
U.S. Pat. No. 3,655,813 issued to F. W. Kirsch et al. discloses a motor fuel alkylation process in which a solid catalyst comprising a Y zeolite is withdrawn from the reaction zone passed into a regeneration zone. A slip stream containing reactants and catalysts is passed from the reaction zone to a separation zone and the separated catalyst is then regenerated by combustion. The process appears to be primarily a liquid-phase operation.
U.S. Pat. No. 5,252,613 issued to M. Chang et al. is directed to enhanced catalyst mixing in a bubble column reactor used for exothermic reactions. Rising gas introduced at the bottom of the column provides the majority of the energy involved in dispersing a particulate catalyst in the liquid in the column. A secondary fluid such as recycle gas or condensed light hydrocarbons is introduced above the gas distributing means.
U.S. Pat. No. 4,827,069 issued to J. D. Kushnerick, et al describes a vapor-phase fluidized bed catalytic process for the conversion of a light olefinic gas feedstock to C.sub.5 -plus hydrocarbons and the conversion of reformate to produce C.sub.7-C.sub.11 aromatic hydrocarbons. Light gas from the top of the reaction zone can be recycled to the reaction zone.